1. Field of the Invention
This invention relates to improved apparatus and methods for reforming hollow articles and, more specifically, it relates to such systems which are adapted to effect precise calibration of hollow articles which are nonsymmetrical or multiplanar, or both.
2. Description of the Prior Art
It has been known for many purposes to reform end portions of a hollow article such as, for example, a hollow metal article in order to remove imperfections or to establish a predetermined size, such as where joinder of the end to another article is desired.
It has been known, for example, to insert an expanding tool into exhaust pipes in automobiles in order to expand the same to effect efficient securement to a muffler or adjacent pipe sections.
U.S. Pat. No. 4,751,839 discloses creation of a flattened end portion on corrugated pipe in order to facilitate joinder to other corrugated pipe sections. This is accomplished by employing a series of movable internal and external dies which cooperate in reforming the pipe end. These die members are moved in and out by means of inner and outer cams.
U.S. Pat. No. 4,380,165 discloses a system for putting a flange on the end of a hollow tube by employing cooperating cammed movable internal and external die elements which are said to resist formation of undesired folds in the hollow tube.
U.S. Pat. No. 4,776,196 discloses formation of flanged workpieces by means of a wedge member which urges movable cheek members outwardly into engagement with the workpiece followed by axial movement of the cheek members.
U.S. Pat. No. 1,039,948 discloses a hydraulically operated pipe flanging machine wherein a pipe flange element is secured to a pipe through hydraulic movement of a mandrel producing responsive radial expansion of internal die members that reform the pipe.
U.S. Pat. No. 3,581,546 discloses a system for removing dents from metal cans and includes the use of an expander plug which moves internal die segments and a tapered shrinking ring to move external dies in order so that the two can cooperate.
U.S. Pat. No. 4,138,873 discloses forming rectangular conduit ends by providing a pair of outer dies which define a rectangular opening therebetween and are positioned in surrounding relationship with respect to the conduit ends. A stationary wedge is inserted into the end interior and a movable wedge is moved into it co-act therewith.
Despite these prior art teachings, there is lacking any teaching of a method of calibrating or reforming the end of a hollow object which is nonsymmetrical. There is also lacking any teaching of calibrating a hollow object which does not have a linear longitudinal axis. There remains, therefore, a real and substantial need for apparatus and methods that will achieve these objectives.